<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
</head>
<body>

<div id="app">
    {{ message }}
    {{a+b}}
</div>


<script>

    var app = new Vue({
        el: '#app',
        data: {
            message: 'Hello Vue1111111!',
            a:1,
            b:2
        }
    })

</script>

</body>
</html>